use learn_axum::configuration::{get_configuration, DatabaseSettings};
use learn_axum::startup::{get_connection_pool, Application};
use learn_axum::telemetry::{get_subscriber, init_subscriber};
use once_cell::sync::Lazy;
use sqlx::{Connection, Executor, PgConnection, PgPool};
use uuid::Uuid;
use wiremock::MockServer;

/// Ensure that the `tracing` stack is only initialised once using `once_cell`
static TRACING: Lazy<()> = Lazy::new(|| {
    let default_filter_level = "info".to_string();
    let subscriber_name = "test".to_string();
    // We cannot assign the output of `get_subscriber` to a variable based on the
    // value TEST_LOG` because the sink is part of the type returned by
    // `get_subscriber`, therefore they are not the same type. We could work around
    // it, but this is the most straight-forward way of moving forward.
    if std::env::var("TEST_LOG").is_ok() {
        let subscriber = get_subscriber(subscriber_name, default_filter_level, std::io::stdout);
        init_subscriber(subscriber);
    } else {
        let subscriber = get_subscriber(subscriber_name, default_filter_level, std::io::sink);
        init_subscriber(subscriber);
    };
});

/// Confirmation links embedded in the request to the email API.
pub struct ConfirmationLinks {
    pub html: reqwest::Url,
    pub plain_text: reqwest::Url,
}

pub struct TestApp {
    pub address: String,
    pub port: u16,
    pub db_pool: PgPool,
    pub email_server: MockServer,
}

impl TestApp {
    pub async fn get_health_check(&self) -> reqwest::Response {
        reqwest::Client::new()
            .get(&format!("{}/health_check", &self.address))
            .send()
            .await
            .expect("Failed to execute request.")
    }
    pub async fn post_subscriptions(&self, body: String) -> reqwest::Response {
        reqwest::Client::new()
            .post(&format!("{}/subscriptions", &self.address))
            .header("Content-Type", "application/x-www-form-urlencoded")
            .body(body)
            .send()
            .await
            .expect("Failed to execute request.")
    }
    pub fn get_confirmation_links(&self, email_request: &wiremock::Request) -> ConfirmationLinks {
        let body: serde_json::Value = serde_json::from_slice(&email_request.body).unwrap();

        // Extract the link from one of the request fields.
        let get_link = |s: &str| {
            let links: Vec<_> = linkify::LinkFinder::new()
                .links(s)
                .filter(|l| *l.kind() == linkify::LinkKind::Url)
                .collect();
            assert_eq!(links.len(), 1);
            let raw_link = links[0].as_str().to_owned();
            let mut confirmation_link = reqwest::Url::parse(&raw_link).unwrap();
            // Let's make sure we don't call random APIs on the web
            assert_eq!(confirmation_link.host_str().unwrap(), "127.0.0.1");
            confirmation_link.set_port(Some(self.port)).unwrap();
            confirmation_link
        };

        let html = get_link(&body["HtmlBody"].as_str().unwrap());
        let plain_text = get_link(&body["TextBody"].as_str().unwrap());
        ConfirmationLinks { html, plain_text }
    }
}

pub async fn spawn_app() -> TestApp {
    // The first time `initialize` is invoked the code in `TRACING` is executed.
    // All other invocations will instead skip execution.
    Lazy::force(&TRACING);

    // Launch a mock server to stand in for Postmark's API
    let email_server = MockServer::start().await;

    // Randomise configuration to ensure test isolation
    let configuration = {
        let mut c = get_configuration().expect("Failed to read configuration.");
        // Use a different database for each test case
        c.database.name = Uuid::new_v4().to_string();
        // Use a random OS port
        c.application.port = 0;
        // Use the mock server as email API
        c.email_client.base_url = email_server.uri();
        c
    };

    // Create and migrate the database
    configure_database(&configuration.database).await;
    let connection_pool = get_connection_pool(&configuration.database);
    let application = Application::build(configuration.clone())
        .await
        .expect("Failed to build application.");
    // Get the port before spawning the application
    let application_port = application.port();
    let address = format!("http://127.0.0.1:{}", application_port);

    // Launch the application as a background task
    tokio::spawn(async move { application.run().await.expect("Failed to run the server") });

    TestApp {
        address,
        port: application_port,
        db_pool: connection_pool,
        email_server,
        // test_user: TestUser::generate(),
        // api_client: client,
        // email_client: configuration.email_client.client(),
    }
}

/// Create a new database and run the migrations.
///
/// # Parameters
/// * `config`: The database configuration.
/// # Returns
/// The connection pool.
async fn configure_database(config: &DatabaseSettings) -> PgPool {
    // Create database
    let mut connection = PgConnection::connect_with(&config.without_db())
        .await
        .expect("Failed to connect to Postgres");
    connection
        .execute(format!(r#"CREATE DATABASE "{}";"#, config.name).as_str())
        .await
        .expect("Failed to create database.");

    // Migrate database
    let connection_pool = PgPool::connect_with(config.with_db())
        .await
        .expect("Failed to connect to Postgres.");
    sqlx::migrate!("./migrations")
        .run(&connection_pool)
        .await
        .expect("Failed to migrate the database");

    connection_pool
}